Enhanced Light–Matter Interactions in Graphene-Covered
Gold Nanovoid ArraysZhuXiaolongShiLeiSchmidtMichael S.BoisenAnjaHansenOleZiJianXiaoSanshuiMortensenN. Asger2016The
combination of graphene with noble-metal nanostructures is
currently being explored for strong light–graphene interactions
enhanced by plasmons. We introduce a novel hybrid graphene–metal
system for studying light–matter interactions with gold-void
nanostructures exhibiting resonances in the visible range. Enhanced
coupling of graphene to the plasmon modes of the nanovoid arrays results
in significant frequency shifts of the underlying plasmon resonances,
enabling 30% enhanced absolute light absorption by adding a monolayer
graphene and up to 700-fold enhancement of the Raman response of the
graphene. These new perspectives enable us to verify the presence
of graphene on gold-void arrays, and the enhancement even allows us
to accurately quantify the number of layers. Experimental observations
are further supported by numerical simulations and perturbation-theory
analysis. The graphene gold-void platform is beneficial for sensing
of molecules and placing Rhodamine 6G (R6G) dye molecules on top of
the graphene; we observe a strong enhancement of the R6G Raman fingerprints.
These results pave the way toward advanced substrates for surface-enhanced
Raman scattering (SERS) with potential for unambiguous single-molecule
detection on the atomically well-defined layer of graphene.